What is the difference between Windows Update and Microsoft Update?

Microsoft Update is essentially a successor to Windows Update and Office Update. Microsoft Update will check for updates to several Microsoft programs besides Windows, including Office applications and server software like Exchange.

If you are not using Microsoft Update, it is easy...once you connect to the Windows Update page (Start/All Programs/Windows Update) you will see a link to use Microsoft Update. Click it and follow through the very short wizard. From then on your PC will connect to Microsoft Update.